Proportioning pump



y 11, 1965 M. MALIZARD ETAL 3,182,597

PROPORTIONING PUMP P/ITTORET fim z m ATTORNEYS Filed April 15, 1965 United States Patent 3,182,597 PRGPORTIGNING PUMP Mar Malizard, 13 Rue Versigny, Paris, Seine, France, and

Andre Pattoret, Chatillon-sous-Bagneux, Seine, France (89 Ave. L. Wiener, Watermael, Belgium) Filed Apr. 15, 1963, Ser. No. 273,1tl2 Claims priority, application France, Apr. 21, 1962, $595,323 Claims. or. res--44) The present invention relates to an all-metal proportioning pump which can be degassed under a vacuum and which is capable of operating in a Wide range of temperatures.

The chief object of the present invention is to permit the suction and delivery of fluids and especially of gases which can either be very clean or highly corrosive by virtue of the fact that all sealing joints have been excluded from the construction of the pump, the assembly of the various components being effected solely by Welding. A further object of the invention is to prevent abrupt overpressures in the pumping circuit While at the same time permitting a particularly high compression rate.

To this end, the proportioning pump in accordance with the invention comprises a pump body which is separated internally into two parts by a transverse partition which delim-its two chambers of identical volume, each of said chambers containing a metallic bellows, one end of which is welded onto the pump body and the other end of which is rigidly fixed to a movable piston, said movable piston providing within said bellows a volume which is variable as a function of the position of said piston inside the chamber, the movable pistons of each of the two chambers being connected to each other through the transverse partition by means of a rigid unidirectional coupling so as to ensure that the maximum compression of one of the bellows corresponds to the maximum extension of the other, and conversely.

The variable-volume space which is formed within the bellows between each piston and the pump body inside the corresponding chamber will be designated in the following description by the terms compression chamber or depression chamber. Each of said chambers is in fact put into communication with a pipe which is used alternately for the suction or delivery of the fluid to be pumped, the reciprocating motion of the pistons being effected as a result of the admission or exhaust of a quantity of driving fluid, for example oil, in the interior of the chambers of the pump body within the space formed between this latter and the external wall of the bellows of the com-.

pression chamber and depression chamber.

The arrangement referred-to above, in which the bellows are mounted to perform a reciprocating motion, makes it possible to obtain a metered volumetric discharge which is practically non-pulsating in the case of the gaseous fluid which is delivered by the pump, said discharge being entirely independent of the pressure of thefiu id. t

As an advantageous feature, each bellows is constructed by means of annular members welded to each other at the peripheral extremities thereof. Each, of the two chambers is also connected by means of a suitable pipe.

to a cyclic distributor which carries out alternately the supply of oil under pressure to said chambers, said dis-' tributor. being in turn connected to a conventional barrel pump, for example. (which has not been illustrated in the drawings). At the end of each stroke, one of the metallic bellows is fully compressed in the interior of the corresponding chamber, and the other bellows is fully 3,182,597 Patented May 11, 1965 extended. There accordingly takes place under such conditions an overpressure in the oil circuit of the barrel feed pump, while said overpressure can be made very substantial without detrimental eifect by virtue of the particular strength of this type of bellows, especially crushing strength. Said overpressure brings about the change-over movement of the distributor and the application of the delivery pressure of the driving fluid to the corresponding chamber. This pressure is then equal to the delivery pressure of the gaseous fluid in the compression and depression chambers Within the bellows and effects in alternate sequence the suction or discharge of said fluid in the circuit in which the proportioning pump is mounted.

Further advantages and characteristic features of the present invention will in any case be more clearly brought out by the description which follows below with reference to one example of embodiment which is given by way of indication and not in any limitative sense.

In the accompanying drawings, the single figure represents in vertical cross-section one form of embodiment of a proportioning pump in accordance with the invention.

As can be seen in this figure, the pump is composed of a body or casing 1 provided with a cent-rial partition wall 2 which delimits two chambers 3 and 4 having substantially equal volumes in the interior of the casing. Said chambers are respectively closed by two head plates 5 and 6 which are maintained in fluid-tight manner against flanges 7 and 8 of the casing 1 by means of screws such as 9.

In the interior of the chamber 3, an annular ring 10 is welded against the inner face or the closure plate 6. A bellows 11 is first welded at one end onto said ring it) and at the other end onto an annular flange 12.. A hollow piston 13 is fitted in said annular flange and is constituted by a plate 14 and a cylindrical cover 15. The plate 14 is pierced with a series of holes 16 and is provided with a central bore 17, the function of which will be explained in detail below.

A chamber 18 is formed within the chamber 3 by the combined assembly which consists of the bellows 11 and the movable piston 13. The volume of said chamber 18 is variable as a function of the position of the piston 13, that is to say of the compression of the bellows 11. (In the case of the figure, the volume of the chamber 18 is at its minimum value).

Inside the chamber 4, there is disposed a deformable member which is substantially similar to that which has just been described in reference to the chamber 3. There also but differs from the piston 13 in that it is not hollow but is made in one piece.

The piston 22 delimits in the interior of the bellows 20 between the inner'face of the closure plate 5 a chamber 23, the volume of which is also variable as a function of the position of the piston, that is to say of the extension or compression of the bellows 2G. 1 (In the example shown in the figure, the chamber 23 has the maximum volume.) v

In accordance with the invention, the two pistons 13 and 2 2 are connectedto each other by means of a unidirectional coupling constituted by a rod 24- Which is adapted to slide freely inside a bore 25 formed at right angles to the partition wall 2 between the chambers 3 and 4. The rod'24 is rigidly secured to the piston Hand is provided for this purpose with a threaded end 26 which is screwed into the interior of a tapped hole 27 formed in the axis of the piston. The other end of the rod 24 is adapted to slide freely through a central bore 17 of the plate 14 of the piston 13 and is provided with a head 28 which is intended to rest on that face of the plate 14 which is directed towards the interior of the piston 13 itself. The chambers 3 and 4 are connected respectively to pipes 29 and 30 through which a driving fluid is admitted into said chambers and exhausted therefrom in alternate sequence, thereby controlling the respective positions of the pistons 13 and 22 which delimit the volume provided in the compression chamber 18 and depression chamber 23.

The chambers 3 and 4 are each provided with an opening for the purpose of draining said chambers. Said openings are formed through bosses such as the boss 31 which are welded at 32 on the casing 1 and are closed off by means of plugs such as the plug which has been designated by the reference 33, each plug having a threaded stem 34 terminating at one end in a spherical portion 35 which is designed to seal off hermetically the communicating passage 36 formed between the interior of the chambers and the corresponding opening.

As the chambers 3 and 4 are connected by the pipes 2.9 and 30 to a fluid circuit which produces the displacement of the pistons, so the chambers 18 and 23 are con nected to the circuit which contains the gaseous fluid to be pumped. To this end, the closure plates 5 and 6 of the casing 1 are provided respectively with an axially bored central connecting-pipe 37 and 38, the central opening being designated by the reference numeral 39 in the case of the connecting-pipe 37 and by the reference numeral 40 in the case of the connecting-pipe 38.

The circuit of the gas to be pumped or delivered is mainly composed of a supply pipe 41 and an outlet pipe 42 which are connected to a piping system by means of which said circuit is put into communication with the chambers 18 and 23 in the manner which will be described in detail below; the admission pipe 41 is welded at right angles to a transverse pipe 43 which terminates at each end in two coupling bushes designated by the reference 44 on the left hand side of the drawing and by the reference 45 on the right. The bush 44 accordingly provides a junction between the pipe 43 and the pipe 46, and similarly, the bush 45 provides a junction between the other end of the pipe 43 and the pipe 47 which is parallel to the pipe 46. The members referred-to above which constitute the gas-admission system are identical to those which constitute the exit system. To this end, the pipe 42 is connected to a transverse pipe 48 which is in turn connected to pipes 49 and 50 by means of bushes S1 and 52, each bush being closed off, as can be seen in that portion of the bush 52 which is shown in cross-section in the figure, by means of a closure plate 53 which is welded at 54 on the bush body.

The two series of pipes 37, 46 and 49 on the one hand, and 38, 47 and 50 on the other hand, are connected respectively to two flow switching systems 55 and 56 which put into communication with the gas circuit the openings 39 and 40 which provide a connection with the variablevolume depression chamber 23 or the variable-volume compression chamber 18.

The flow-switching system 55 consists of a connectingpiece which is hollowed-out internally so as to permit a seating member 58 to be housed therein. The connection between the flow-switching unit 55 and the pipe 46 is direct and can be closed ofl by means of a valve constituted by a single ball 59 which is capable of being applied against the cone-shaped internal wall 57 of the body of the flow-switching unit 55. Similarly, the pipe 49 which terminates in the interior of the seating 58 can be closed off by means of a ball 60 which is brought to bear against the internally cone-shaped wall 61 of said seating member 58. 7

The flow-switching unit 56 which corresponds to the chamber 3 and variable-volume chamber 18 is designed in a manner which is exactly similar to the flow-switching unit 55. Accordingly, balls 62 and 63 which form valves for the purpose of closing or opening the pipes epending on whether said balls are either applied against or freed from the conical seatings 63 and 64 which are formed in the body of the flow-switching unit 56.

The operation of the proportioning pump in accordance with the invention can readily be deduced from the foregoing.

Accordingly, the chamber 3 is assumed to be filled with oil supplied through the pipe 29 of a cyclic distributor, that is to say an apparatus of conventional type comprising a moving slide-valve combined with calibrated valves, and which delivers either in one or in the other of the chambers 3 and 4 of the proportioning pump, the oil consequently producing the displacement of the pistons 13 and 22. The piston 13 is located in the position which is shown in the figure; the volume of the chamber 18 is at a minimum and the gas initially contained in said chamber is driven out through the pipe 40, thereby causing the ball 62 to be applied against the corresponding seating 64 and to close off the pipe 47, whilst the ball 63 is disengaged from its seating 65 and allows free access to the pipe 50. The gas is thus forced towards the exit pipe 42.

Under the influence of the overpressure which arises in the oil circuit at the time of full compression of the bellows 11, the cyclic distributor changes over at this moment, and a certain quantity of oil is delivered into the chamber 4 through the pipe 30. The piston 22 is then driven back towards the closure plate 5 while the piston 13 moves away from the plate 6 over a same distance by virtue of the coupling provided by the rod 24 between the pistons 22 and 13. The volume of the chamber 23 decreases and the gas contained therein is forced through the pipe 39 and then escapes into the pipe 49 since the ball 59 ensures the closure of the pipe 46 as a result of the application of said ball against the seat 57 whereas the ball 60 which is freed from its seating 61 provides at the same time a communication between the pipes 39 and 49. There takes place at the same time a reduction in volume of the chamber 23 and an equivalent increase in volume of the chamber 18. The oil contained in the chamber 3 is forced out through the pipe 29. The balls 62 and 63 of the flow-switching system 56 are then thrust back so as to permit the admission of gas into the chamber 18 through the assembly of pipes 41, 43, 47 and 40.

The cycle described above is thus symmetrically reproduced as controlled by the change-over movements of the cyclic distributor, the chambers 18 and 23 operate alternately in compression or in depression in order to permit of the suction or delivery of the gas.

Among the advantages gained by means of a proportioning pump of this design, particular emphasis should be laid on the fact that the metallic bellows which are employed are practically always in a condition of pressure equilibrium between the gas to be compressed and the oil constituting the driving fluid. Even at very high delivery pressures, these bellows can be constructed of thin sheeting which permits of very substantial movements of extension.

The pump itself can be of very small size, and can thus be located at a substantial distance away from the control circuit and the cyclic distributor, thereby making the use of said pump advantageous, especially in contaminated enclosures for the purpose of pumping radioactive gases. It should also be pointed out that the driving fluid can serve if necessary as a cooling agent or heating agent depending on the conditions of use, in view of the fact that, as has already been stated in the foregoing, the pump is not fitted with any sealing joint of plastic material or the like which is liable to become damaged.

The all-metal construction of the various components of the pump finally permit the use of this latter over a very wide range of temperatures, the circuit which is designed for the circulation of gas being constructed of parts which are welded together and which can therefore be readily degassed. It is also useful to note in this connection that the bellows, pistons, etc., can readily be repaired or replaced by virtue of the use of removable plates which serve to close off the two chambers of the pump body.

Lastly, a further advantage of the pump lies in the use of a unidirectional coupling for the purpose of connecting the two operating pistons together. The said coupling is in fact permitted to remain free in the direction of extension of the bellows (the rod 24 is capable of sliding freely inside the hollow piston 13 through the bore 17) in such manner that said bellows can accordingly absorb without any danger the abrupt overpressures which are liable to occur on the gas-suction side.

It will be understood that the present invention is not limited in any respect to the form of embodiment which has been described and illustrated and which has been given solely by way of example.

What we claim is:

1. A proportioning pump for gaseous fluid comprising a pump body, a transverse partition dividing said body internally into two chambers of substantially identical volume, characterized in that a metallic bellows is disposed in each of said chambers, one end of said bellows being secured to the pump body, a movable piston disposed within and closing the other end of each of said bellows and being rigidly fixed thereto, said movable piston providing within said bellows a volume which is variable as a function of the position of said piston inside the chamber, a rigid unidirectional coupling connecting the movable pistons of the two chambers to each other through the transverse partition; means for connecting the interior of each of said bellows to a gaseous fluid proportioning circuit; and means for connecting each of said chambers to a fluid motor circuit.

2. A proportioning pump in accordance with claim 1, characterized in that a removable head plate closes each chamber, and said one end of the bellows contained in said chambers is secured to said removable head plate of the respective chamber by welding.

3. A proportioning pump in accordance with claim 1, characterized in that the internal variable volume of each bellows is connected to the circuit of the gaseous fluid to be pumped, and a flow-switching system communicating with said gaseous fluid circuit which permits the admission and delivery of said gaseous fluid following the movements of extension and compression of said bellows.

4. A proportioning pump in accordance with claim 3, characterized in that each flow-switching system includes a part provided with a pair of spaced-apart, oneway check valves permitting gaseous fluid to flow freely in one direction in said circuit, said means connecting said bellows to said gaseous fluid circuit, including a pipe connected to said part intermediate said check valves, thereby closing oif or freeing the passage of gaseous fluid as a function of the movements of extension and compression of the bellows.

5. A proportioning pump in accordance with claim 1, characterized in that the rigid coupling between the two pistons is constituted by a rod, one end of said rod being threaded and screwed into one of said pistons and the other end of said rod being provided with a head which bears on the inner surface of the second piston and which is free to slide in the interior of said second piston so as to absorb any abrupt overpressures occurring within the bellows at the time of suction of the gaseous fluid.

6. A fluid pump comprising: a closed pump body; a transverse partition dividing the interior of said body into two chambers; a bellows within each of said chambers fixed at one end thereof to said pump body; a rigid wall closing the other end of each of said bellows; a rigid member extending in sliding engagement through said partition and connected at the opposite ends thereof to said rigid Walls; means for connecting the interior of said bellows to a fluid pumping circuit; and means for connecting each of said chambers to a fluid motor circuit, whereby fluid under pressure directed alternately to said chambers compresses the bellows in the chamber under pressure and pumps the fluid therein into said pumping circuit while at the same time the bellows in the other chamber extends and draws thereinto fluid to be pumped.

7. A proportioning pump for fluid comprising: a closed pump body; a transverse partition dividing the interior said body into two chambers of substantially equal volume; a bellows within each of said chambers fixed at one end thereof to said pump body; a rigid wall closing the other end of each of said bellows, said bellows being of substantially equal volume, a rigid member extending in sliding engagement through said partition and connected at the opposite ends thereof to said rigid walls; means for connecting the interior of said bellows to a fluid pumping circuit; and means for connecting each of said chambers to a fluid motor circuit, whereby fluid under pressure directed alternately to said chambers compresses the bellows in the chamber under pressure and pumps the fluid therein into said pumping circuit while at the same time the bellows in the other chamber extends and draws thereinto fluid to be pumped.

8. A proportioning pump for fluid comprising: a closed pump body; a transverse partition dividing the interior said body into two chambers; a bellows within each of said chambers fixed at one end thereof to said pump body; a piston disposed within the other end of each of said bellows and with the outer end thereof fixed to and closing the other end of the respective bellows, said pistons fitting closely within but spaced from the inner wall of the bellows associated therewith; a rigid member extending in sliding engagement through said partition and connected at the opposite ends thereof to said pistons; means for connecting the interior of said bellows to a fluid pumping circuit; and means for connecting each of said chambers to a fluid motor circuit, whereby fluid under pressure directed alternately to said chambers compresses the bellows in the chamber under pressure and pumps substantially all of the fluid therein into said pumping circuit While at the same time the bellows in the other chamber extends and draws therinto fluid to be pumped.

9. A proportioning pump for fluid comprising: a closed pump body; a transverse partition dividing the interior said body into two chambers; a bellows within each of said chambers fixed at one end thereof to said pump body; a piston disposed within the other end of each of said bellows and with the outer end thereof fixed to and closing the other end of the respective bellows, said pistons fitting closely within but spaced from the inner wall of the bellows associated therewith; a rigid member extending in sliding engagement through said partition, said member being rigidly connected at one end thereof to one of said pistons and unidirectionally connected at the other end thereof to the other of said pistons; means for connecting the interior of said bellows to a fluid means for connecting each of said chambers to a fluid motor circuit, whereby fluid under pressure directed alternately to said chambers compresses the bellows in the chamber under pressure and pumps substantially all of the fluid therein into said pumping circuit while at the same time the bellows in the other chamber extends and draws thereinto fluid to be pumped.

10. A fluid pump comprising: a closed pump body; a transverse partition dividing the interior said body into two chambers; a bellows within each of said chambers fixed at one end thereof to said pump body; a rigid wall closing the other end of each of said bellows; a rigid member extending in sliding engagement through said partition and connected at the opposite ends thereof to said rigid walls; a fluid pumping circuit connected to the interior of said bellows; a pair of spaced-apart, one-way pumping circuit; and

7 check valves in said fluid pumping circuit permitting fluid to fiow freely therethrough in one direction, the interior of said bellows being connected to said fluid pumping circuit intermediate said check valve; and means for connecting each of said chambers to a fluid motor circuit,

whereby fluid under pressure directed alternately to said chambers compresses the bellows in the chamber under pressure and pumps the fluid therein into said pumping circuit while at the same time the bellows in the other chamber extends and draws thereinto fluid to be pumped. 10

8 References Cited by the Examiner UNITED STATES PATENTS 2,613,610 10/52 Saalfrank 103148 FOREIGN PATENTS 796,685 4/36 France.

LAURENCE V. EFNER, Primary Examiner. ROBERT M. WALKER, Examiner. 

1. A PROPORTIONING PUMP FOR GASEOUS FLUID COMPRISING A PUMP BODY, A TRANSVERSE PARTITION DIVIDING SAID BODY INTERNALLY INTO TWO CHAMBERS OF SUBSTANTIALLY IDENTICAL VOLUME, CHARACTERIZED IN THAT A METALLIC BELLOW IS DISPOSED IN EACH OF SAID CHAMBERS, ONE END OF SAID BELLOWS BEING SECURED TO THE PUMP BODY, A MOVABLE PISTON DISPOSED WITHIN SAID CLOSING THE OTHER END OF EACH OF SAID BELLOWS AND BEING RIGIDLY FIXED THERETO, SAID MOVABLE PISTON PROVIDING WITHIN SAID BELLOWS A VOLUME WHICH IS VARIABLE AS A FUNCTION OF THE POSITION OF SAID PISTON INSIDE THE CHAMBER, A RIGID UNIDIRECTIONAL COUPLING CONNECTING THE MOVABLE PISTONS OF THE TWO CHAMBERS TO EACH OTHER THROUGH THE TRANSVERSE PARTITION; MEANS FOR CONNECTING THE INTERIOR OF EACH OF SAID BELLOWS TO A GASEOUS FLUID PROPORTIONING CIRCUIT; AND MEANS FOR CONNECTING EACH OF SAID CHAMBERS TO A FLUID MOTOR CIRCUIT. 